1. Field of the Invention
The present invention relates to a double locked terminal connector having a holder. In an incomplete insertion state of a terminal into a housing of the connector, a locking arm for the terminal abuts against the holder, which notices the incomplete insertion of the terminal. In a complete insertion state of the terminal, the extended piece prevents the deflection of the terminal to double lock the terminal in the connector housing.
2. Related Art
FIGS. 5 to 8 show a known double locked terminal connector.
As illustrated in FIG. 5, the double locked terminal connector 40 has a plug connector housing 41 made of a synthetic resin material, a receptacle terminal 28 connected to an electrical wire, and a front holder 42 made of a synthetic resin material. The terminal 28 is inserted from a rear opening of the connector housing 41 into a terminal accommodation chamber 17. The holder engages with a forward end portion of the connector housing 41 and locks the terminal 28 in the connector housing 41.
The connector housing 41 has a resilient locking arm 5 formed therein. The locking arm 5 has a lock protrusion 13 which is protruding into the terminal accommodation chamber 17 when the locking arm 5 is free. In a complete insertion state of the terminal 28 into the terminal accommodation chamber 17, the protrusion 13 of the locking arm 5 can engage with a locking opening (not shown) formed in a base portion 30 of the terminal 28. The base portion 30 has a box-shaped electrical connection portion 29 unitarily formed therewith at one side thereof. The electrical connection portion 29 has a resilient contact piece (not shown) formed therein. The base portion 30 has an electrical wire connection portion (crimping portion) 43 at the other side thereof.
In FIG. 5, the terminal 28 is in a half insertion state. The protrusion 13 of the locking arm 5 abuts against the base portion 30 of the terminal 28, so that the locking arm 5 is deflecting toward a deflection space 22 formed in the connector housing 41. The connector housing 41 is formed with an insertion space 44 of a hollow or a channel shape for receiving the front holder 42. The insertion space 44 is extending toward a fore side of the connector housing 41 so as to be contiguous to the deflection space 22.
The front holder 42 is of a substantially rectangular frame shape. The holder 42 has an extended piece 45 of a small width plate which can be inserted into the insertion space 44. The extended piece 45 extends from a front wall 8 of the holder 42 in a longitudinal direction of the housing inside a frame wall 7 of the holder 42. The frame wall 7 engages with a forward outer surface of the connector housing 41. Optionally, the connector housing 41 has a hood (not shown) unitarily formed with the housing 41 with a clearance from an outer surface of the housing 41. The front holder 42 slides into and engages with the connector housing 41 opposite to the terminal insertion direction.
As illustrated in FIG. 5, in an incomplete insertion state of the terminal 28, a fore end of the locking arm 5 which is deflecting abuts against the tip of the extended piece 45. This prevents a further advancement of the front holder 42 to notice the incomplete insertion of the terminal 28.
Meanwhile, in a complete insertion state of the terminal 28 into the terminal accommodation chamber 17, the protrusion 13 of the locking arm 5 enters the electrical connection portion 29 of the terminal 28, so that the locking arm 5 returns to its free position. Thus, the extended piece 45 does not abuts against the locking arm 5 to advance into the insertion space 44, so that the extended piece 45 prevents the movement of the locking arm 5 to lock the terminal 28. That is, the extended piece 45 serves to inspect an incomplete insertion state of the terminal 28 and also to lock the terminal 28. The extended piece 45 described above prevents the movement of the locking arm 5 to surely lock the terminal. In another example of a terminal double locking connector (not shown), an extended piece directly locks a shoulder 46 of the electrical connection portion 29 of the terminal 28.
FIG. 6 shows a preliminary engaging state of the front holder 42 with the connector housing 41, and FIG. 7 shows a complete engaging state of the front holder 42 with the connector housing 41.
For the front holder 42 and the connector housing 41, there are provided a preliminary locking means and a final locking means (not shown). The preliminary locking means consists of a preliminary locking protrusion and a preliminary lock opening. The final locking means consists of another locking protrusion and another lock opening. In the preliminary engaging state of the front holder 42 of FIG. 6, the terminal accommodation chamber 17 receives the terminal 28 (FIG. 5).
After the insertion of the terminal, the front holder 42 is pushed toward the terminal side to engage with the connector housing 41. Then, the front holder 42 becomes in a finally locked state as illustrated in FIG. 7. In the finally locked state, the extended piece 45 limits the movement of the locking arm 5.
However, in the above-mentioned constitution, as illustrated in FIG. 8, the position of the extended piece 45 is unstable within the insertion space 44 when the terminal 28 is incompletely inserted into the connector housing 41. Furthermore, there are dimensional tolerances of the extended piece 45 and the insertion space 44 to cause an inadequate looseness between them. Thus, the position of the extended piece 45 is variable within the insertion space 44, so that the fore end of the locking arm 5 which is deflecting abuts against the extended piece 45 with a variable abutment area. As illustrated in FIG. 8, there is no problem when the best abutting distance A is achieved. However, when the locking arm 5 abuts against the extended piece 45 with the smallest abutting distance B, the locking arm 5 may be pushed toward the terminal side. This enlarges a clearance 47 of the insertion space 44 to release the extended piece 45 from the locking arm 5. Thus, there is the disadvantage that the extended piece 45 unintentionally advances into the insertion space 44.
Furthermore, in a final locking state of the front holder 42 as illustrated in FIG. 7, there may be a variable clearance 48 between the locking arm 5 and the extended piece 45 due to the variable position of the extended piece 45. Thus, the locking arm 5 tends to deflect so that the locking arm 5 disadvantageously provides a reduced locking force on the terminal. The reduced locking force may disengage the terminal 28 from the connector housing 41. These disadvantages of the front holder 42 are found also when a rear holder (not shown) is coupled to a rear portion of a connector housing to limit the movement of a locking arm for locking a terminal. In this connector, the locking arm is extending rearward.
In view of the disadvantages, an object of the present invention is to provide a double locked terminal connector in which an incomplete insertion state of a terminal is reliably recognized. In an incomplete insertion state of the terminal in a connector housing, a fore end of a locking arm surely abuts against an extended piece of a holder.
For achieving the object, a double locked terminal connector according to the invention includes a connector housing having a resilient locking arm for locking a terminal. The connector also includes a holder having an extended piece inserted into an insertion space of the connector housing. In an incomplete insertion state of the terminal, the locking arm deflects so that a free end surface of the locking arm protrudes from an inner wall of the insertion space to cause the extended piece to abut against the free end surface of the locking arm. Meanwhile, in a complete insertion state of the terminal, the extended piece is inserted into the insertion space to lie over the locking arm. The extended piece is longitudinally inclined toward the locking arm so that the extended piece can slidingly contact the inner wall of the insertion space.
Preferably, the inner wall of the insertion space has an inclined portion at an intermediate portion of the inner wall for guiding the extended piece. The free end surface of the locking arm is positioned so as to cross a longitudinally mid or inner end point of the inclined portion when the locking arm is deflected.
Preferably, in an initial insertion state of the holder in the connector housing, the extended piece is positioned at a widened entrance of the insertion space. The widened entrance is contiguous to the insertion space. A forward end of the extended piece resiliently contacts a portion of the inner wall of the insertion space when the holder is inserted. The portion is contiguous to the inner end of the inclined portion.
Preferably, the forward end surface of the extended piece is inclined parallel to the free end surface of the locking arm.